1. Field of the Invention
The invention relates to a semiconductor structure and manufacturing method thereof, and more particularly, to a semiconductor structure with a specific shaped epitaxial recess and manufacturing method thereof.
2. Description of the Prior Art
With semiconductor processes entering the era of the deep submicron meter below 65 nanometer (nm), it has been more and more important to increase the metal-oxide semiconductor (MOS) drive current. To improve device performance, a strained-silicon technique such as a selective epitaxial growth (SEG) method is developed to form epitaxial layers serving as the source/drain of the MOS. Because a lattice constant of the epitaxial layer is different from that of silicon, such characteristic is employed to cause alteration to the band structure of the silicon in the channel region. Accordingly, carrier mobility of the channel region is enhanced and thus device performance is improved.